Conflicting Health-Related Scientific Evidence in News Reports: Effects of Hedging and Presentation Format on Perceived Issue Uncertainty and Scientists’ and Journalists’ Credibility

Introduction: This study examined effects of two journalistic practices in reporting conflicting scientific evidence, hedging and presentation format, on scientists’ and journalists’ credibility and issue uncertainty. Methods: An online experiment was conducted using students from a western U.S. university. Hedging was manipulated as reporting methodological limitations versus not reporting the limitations in news articles covering the conflict. Presentation format was manipulated as using a single news article to report both sides of the conflict versus using double articles with one side of the conflict in one article and the other side in the other article. Results: The study found that perceived issue uncertainty was higher in hedged news articles than that in non-hedged articles; presentation format did not affect people’s perceived issue uncertainty. For scientists’ credibility (both competence and trustworthiness), this study found that it was lower in the single-article format than that in the double-article format; for journalists’ credibility, this study found that journalists’ trustworthiness in the two formats did not vary, but their competence was lower in the double-article format than that in the single-article format. Conclusion: This study contributes to the field of science and health communication by examining effects of presentation format used in communicating conflicting health-related scientific evidence and by examining effects of communicating scientific limitations in a context where conflicting evidence exists. Keywords: conflicting scientific evidence, hedging, presentation format, scientists’ credibility, journalists’ credibility